Biology · Biological Molecules
Work through this past-paper style MCQ, then read the full explanation. Practice more biology questions on mMCQ with adaptive practice and topic analytics.
Identify the CORRECT option that matches the sugar with its carbon number and functional group:
- A
Glyceraldehyde Triose, Ketone group
- B
Ribose-Pentose, Aldehyde-group
- C
Ribulose Pentose, Aldehyde Group
- D
Galactose Hexose, Ketone Group
The correct answer is option B: Ribose-Pentose, Aldehyde-group. Ribose is a five-carbon sugar known as a pentose, and it has an aldehyde functional group, which is characteristic of aldoses. The other options are incorrect due to mismatches between the sugar type (triose, pentose, hexose) and their respective functional groups. Specifically, glyceraldehyde is a triose and has an aldehyde, not ketone; ribulose is a pentose but contains a ketone group; and galactose, despite being a hexose, has an aldehyde group rather than a ketone.
This option incorrectly identifies glyceraldehyde as having a ketone group. Glyceraldehyde is a triose sugar with an aldehyde group, not a ketone.
This is the correct option. Ribose is a pentose sugar (5 carbons) and contains an aldehyde group, making it a key component of nucleotides.
This option describes ribulose correctly as a pentose, but ribulose actually contains a ketone group, not an aldehyde group.
This option incorrectly states that galactose has a ketone group. Galactose is a hexose sugar with an aldehyde group.
Tagged under Biology · Biological Molecules · 2025